Audio - Qualcomm Dragonwing Documentation

The IQ-9075 audio subsystem is powered by Low Power AI (LPAI) and delivers advanced voice UI and audio experiences via PipeWire.

Key Features

Low Power AI (LPAI) subsystem for efficient audio processing
PipeWire multimedia server for low-latency audio routing
Hardware-accelerated encoding/decoding
Fluence ECNS — advanced echo cancellation and noise suppression
Multiple audio interfaces — I2S, TDM, SoundWire

Hardware Configuration

Speakers: Onboard speakers with MAX98357 I2S-amps; HS0_MI2S shared between left and right for stereo
Microphone: Single onboard microphone (MMICT5848) on HS2_MI2S, configured to left channel by default

Speaker connection:

Architecture

Component	Description
PipeWire	Multimedia server; replaces PulseAudio; low-latency, flexible media handling
WirePlumber	Session/policy manager; handles default sink/source, auto-connect rules
PAL	Platform Abstraction Layer; provides audio-specific APIs and DSP graph operations
AGM	Audio Graph Manager; ALSA-based mixer controls and PCM/compressed plug-ins
ARGS/GSL	AudioReach Graph Service; handles initialization and creation of audio graphs
SPF	Signal Processing Framework; modular framework on LPAI DSP

Configuration Files

Component	Location
ALSA card registration	`/proc/asound/cards`
WirePlumber rules & config	`/usr/share/wireplumber/`

Verify Audio Stack

# Confirm ALSA card and devices
cat /proc/asound/cards
aplay -l
arecord -l

# Confirm PipeWire + WirePlumber services
systemctl  status pipewire wireplumber --no-pager

# Validate default sink/source
wpctl status

# Monitor graph
pw-top
pw-cli ls Node

Audio Playback and Capture

PipeWire Playback

Push audio file to device

scp test.wav root@<ip-addr>:/opt/

Set default sink and volume

wpctl status   # Find sink node marked with *
wpctl set-default <sink-node>   # If not already set
wpctl set-volume @DEFAULT_AUDIO_SINK@ 1.0

Play audio

pw-play /opt/test.wav -v

The command shell should resemble the following:

Press Ctrl+C to stop.

PipeWire Record

Set default source and volume

wpctl status   # Find mic node marked with *
wpctl set-default <mic-node>   # If not already set
wpctl set-volume @DEFAULT_AUDIO_SOURCE@ 1.0

Start recording

pw-record /opt/record.wav -v

The command shell should resemble the following:

Press Ctrl+C to stop.

A value of 1.0 represents 100% volume.

GStreamer Audio

Capture
Playback

# PCM capture
gst-launch-1.0 -v pulsesrc volume=10 ! audioconvert ! wavenc ! \
  filesink location=/opt/audio.wav

# FLAC capture
gst-launch-1.0 -v pulsesrc volume=10 ! audioconvert ! flacenc ! \
  filesink location=/opt/audio.flac

# WAV playback
gst-launch-1.0 -e filesrc location=/opt/audio.wav ! \
  wavparse ! audioconvert ! pulsesink volume=10

# MP3 playback
gst-launch-1.0 -e filesrc location=/opt/audio.mp3 ! \
  mpegaudioparse ! mpg123audiodec ! pulsesink volume=10

# FLAC playback
gst-launch-1.0 -e filesrc location=/opt/audio.flac ! \
  flacparse ! flacdec ! pulsesink volume=10

Log Capture

# PipeWire logs
journalctl -u pipewire
journalctl  -u wireplumber

# Live debugging
journalctl -u pipewire -f

# Kernel audio driver logs
sudo dmesg

Troubleshooting

No Audio Output During Playback

wpctl status
wpctl set-volume @DEFAULT_AUDIO_SINK@ 1.0
systemctl restart pipewire pipewire-pulse wireplumber

pw-play /opt/test.wav -v

# Check services
systemctl status pipewire pipewire-pulse wireplumber

Audio Playback Stuttering or Crackling

# Check CPU load
top

# Check PAL media config (expect rate=48000, ch=2, fmt=2)
grep "setDeviceMediaConfig" /var/log/syslog

# Check for underruns
dmesg | grep -i -e underrun -e xrun -e lpass -e audio

# Check PipeWire quantum
pw-metadata -n settings

# Monitor real-time
pw-top

Fix — increase PipeWire buffer:

mkdir -p ~/.config/pipewire/pipewire.conf.d
cat > ~/.config/pipewire/pipewire.conf.d/99-custom-buffer.conf << 'EOF'
context.properties = {
    default.clock.quantum = 1024
    default.clock.min-quantum = 1024
}
EOF
systemctl restart pipewire wireplumber

Fix — convert audio to 48 kHz 16-bit stereo:

ffmpeg -i input.wav -ar 48000 -ac 2 -sample_fmt s16 output.wav

PipeWire Service Not Starting

systemctl status pipewire pipewire-pulse wireplumber
journalctl -u pipewire -u wireplumber -b

# Reset configuration
rm -rf ~/.config/pipewire ~/.config/wireplumber
systemctl  daemon-reload
systemctl  restart pipewire pipewire-pulse wireplumber

# Reinstall if needed
sudo apt install --reinstall pipewire wireplumber pipewire-pulse

Advanced Features

Echo Cancellation (ECNS) for VoIP

# VoIP record
pw-record /opt//record_voip.wav -v --target=voip-tx0

# VoIP playback
pw-play /opt/record_voip.wav -v --target=voip-rx0

Features: adaptive echo cancellation, stationary and non-stationary noise suppression, acoustic echo path cancellation.

​Key Features

​Hardware Configuration

​Architecture

​Configuration Files

​Verify Audio Stack

​Audio Playback and Capture

​PipeWire Playback

​PipeWire Record

​GStreamer Audio

​Log Capture

​Troubleshooting

​Advanced Features

​Echo Cancellation (ECNS) for VoIP

​Resources

Key Features

Hardware Configuration

Architecture

Configuration Files

Verify Audio Stack

Audio Playback and Capture

PipeWire Playback

PipeWire Record

GStreamer Audio

Log Capture

Troubleshooting

Advanced Features

Echo Cancellation (ECNS) for VoIP

Resources